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Everwide Newsletter No.304


Experiment § Arc resistance tester

According to ASTM D495, the abbreviation of "Standard Test Method for High-Voltage, Low-Current, Dry Arc Resistance of Solid Electrical Insulation" is Arc resistance. Put a test piece on electrodes 6.35mm apart, and apply voltage of 12.5kV and arc current of 10mA. The relationship between test piece, electrodes and tester is shown in Figure 1; figure 2 is the overall appearance of the tester. At the beginning, intermittently applied the arc, for example, 1/4 second for power-on and 1 ¾ second for power-off, gradually increasing the time of power-on to continuous power-on (Figure 3); the current will gradually increase from 10mA to 40mA. Different test standards such as ASTM D495, IEC 61621, GB 1411-78, etc., has different current intensity and power-on time per minute. Since surface of the test piece is affected by high temperature of arc, carbonization will first occur near electrodes (Figure 4). As arc time increases, appearance of black carbonized lines (Figure 5), disappearance of conducting arc, burning of the test piece (Figure 6), etc. all indicate that the test piece has failed. Different materials have different destroying times, so arc resistance of materials is evaluated according to the number of seconds of failure. The arc resistance time of pure epoxy resin is about 30-60 seconds, but the formula of adding a large amount of quartz powder is about 120 seconds.

─Author: Chia-Ching, Lin

 

Activity § Passionate July

In addition to visiting the environment when registering, summer interns also took cover photos in the garden for the intern manual (Figure 1). During the internship, not only can them experience the joy and hardship of work, but R&D staffs will also teach students professional knowledge of machines (Figure 2). Hopes everyone can gain something from the two-month internship. The intention of holding annual non-warning fire drills is to simulate possible situations to respond to emergencies (Figure 3), and also experience the hard work of firefighters wearing heavy protective equipment. Thanks to the firefighters for hard-working.

 

Knowledge § What are specific strength and specific modulus?

Specific strength refers to material’s strength divided by its density, that is, it means strength per unit density, and the unit is MPa/(g/cm³). Some materials have same strength when they are in same shape, but the density of the two are very different, so specific strength are different, too. Take aluminum and stainless steel as examples, the tensile strength of the two are similar, but density of the former is 2.9 and the latter is 7.9, so specific strength of the two differs by more than 3 times. In other words, in the design of same strength, the weight of aluminum is 1/3 of that of stainless steel; or it can also be said that aluminum is three times the weight of stainless steel in the same weight. Specific modulus refers to elastic modulus divided by density, that is, it means the elastic modulus per mass density, and the unit is GPa/(g/cm³). The higher the specific modulus of the material, the higher the rigidity of the same part; At the same rigidity, the higher the specific modulus, the lighter the material.

 

Living § Studious Youth II

“Studios Youth II” had started since March this year. The content of the activity was that each group shared review after discussion. Participants and Mr. Yu would ask questions and gave feedback. What was valuable was that since everyone usually performs their own duties in the work position, it was a great experience to be able to get together and share and discuss with colleagues in various departments. In addition to analyzing what can be done to improve the common good, we also discussed other issues. For example, what kind of company is Everwide? What kind of employees can make Everwide better? I think there is no absolute answer to these questions. Flat organization relies on everyone to complete their work and coordinate with each other. What impressed me the most was the process of producing the briefing: From the discussion and reaching consensus, the reporter consolidated the information and produced a briefing, and the team conducted the initial test report, and then final confirmation within the grou. After Mr. Yu’s suggestion and practiced many times, everyone made lots of progress. Einstein said, “Insanity: doing the same thing over and over again and expecting different results.” Let's study hard and work happily together.

─Author: Hsin-Hsin, Shih


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